GB2268407A - Device for the disposal of hypodermic needles - Google Patents

Abstract

A hypodermic needle destruction device is provided in which a pair of electrodes (5a, 5b) are adapted to make contact with a hypodermic needle (8) at spaced positions to heat and destroy the portion of needle between these positions as the needle is fed, roughly axially, towards the electrodes. Means are provided, for rendering one electrode (5b) movable somewhat towards the other, for decreasing the space between the electrodes when pressure is exerted so that the decreased spacing can be used to destroy a needle right up to its base and thereby avoid any residual needle stubs. The device is preferably battery powered and preferably completely self- contained with provision for recharging or replacing the battery. <IMAGE>

Description

THE DISPOSAL OF HYPODERMIC NEEDLES AND OPTIONALLY ASSOCIATED SYRINGES THE DISPOSAL OF HYPODERMIC NEEDLES AND, OPTIONALLY ASSOCIATED SYRINGES.

FIELD OF THE INVENTION This invention relates to the disposal of hypodermic needles and, optionally, as may be required, hypodermic syringes associated therewith in a manner such that the disposal of such needles and syringes may be most efficiently carried out, but with substantial safety to persons handling waste which contains the remains of hypodermic needles and syringes.

BACKGROUND TO THE INVENTION This is a fear, and a real danger, that personnel working with patients who have, the HIV, Hepatitis B or Hepatitis C viruses, as well as other germs and viruses, could become infected in consequence of accidental contact with the virus. Such contact would most commonly take place in the event of medical, cleaning, or waste disposal personnel breaking their skin, for example, with a hypodermic needle. Such action is commonly known as a "needlestick".

Sterilising hypodermic needles is regarded as old fashioned and, in any event, not entirely effective. In consequence, various devices have been proposed which incinerate the major part of the length of a hypodermic needle down to a position short of the base of the needle whereby it is joined to a syringe. Some of the incineration devices, such as that described in US Patent Number 4628169, have a detaching device for detaching the base of a needle from a syringe after it has been incinerated as indicated above.

The electrodes carrying out the incineration comprise two axially (relative to the needle axis) spaced, fixed electrodes arranged to contact spaced positions along the length of a hypodermic needle, starting from the pointed end, so that the portion of the needle between the electrodes becomes heated to destruction by resistance heating. The needle is then fed axially towards the electrodes to continue this process to destroy the major portion of the length of the needle down to a position short of the base thereof.

British Patent Number 2211420, on the other hand, proposes a pair of pinched rollers as electrodes at least one of which is resiliently urged towards the other in a direction transverse to the needle axis in use. Accordingly, an electric current, in order to incinerate the needle, must pass across the diameter thereof and so incinerate the needle as it is fed between the rollers. Applicant does not consider this to be an effective electrode arrangement but, be that as it may, this arrangement also leaves a residual length of needle adjacent to the base (hereinafter called a "stub").

European Patent Number 374439 describes an incineration device in which two elongate convergent electrodes are provided. The proposal, is that a needle is initially brought into contact at its end adjacent the base, and at its point, with the electrodes at their more divergent ends and the needle is then slid towards the converging ends of the electrodes to progressively incinerate the needle. Applicant believes that this arrangement will not work in view of the fact that it can happen that a central region of the needle becomes incinerated initially, should there be a high resistance zone due to non-uniform wall thickness, for example. This may cause short lengths of un-incinerated needle to be formed.

Also an extremely high voltage, relatively speaking, is required to initiate incineration where the whole length of the needle is bridged between the two electrodes in the manner proposed.

European Patent Application Number 332584 also describes a hypodermic needle destruction device similar in basic operation to that of US Patent 4628169 and which also leaves a needle stub adjacent the base after incineration of the needle.

Applicant considers it undesirable that a needle stub be left on the base in view of the fact that this still leaves a waste disposal problem. The same applies to the short lengths of needle which can form in the case of the apparatus having convergent, elongate electrodes. The difficulty is that needle bases with stubs, or short lengths of needle, are unacceptable as normal waste and cannot be disposed of in a normal waste bag made of plastic as they will tear or punture the bag.

Accordingly such hypodermic needle remnants must be disposed of with great care. One method is to use so-called "Sharps bins" which are rigid plastics bins and wherein the entire bin and its' contents are, once the bin is full, incinerated. The burning of such additional plastic is undesirable in that it results in additional air polution. Not only this, but, after the needle base has been removed as is the case in most hypodermic needle incinerators, the leftover pharmaceutical preparation in the syringe can leak out and can also constitute a danger or threat.

Applicant believes, accordingly, that it would be useful to render at least hypodermic needle bases discardable in the normal course of the events to thereby avoid the use of costly "sharps bins".

It is furthermore to be noted that all of the hypodermic needle incinerating devices mentioned above operate on AC power supply apart from the case of European Patent Application Number 0374439 which proposes a rechargable battery arrangement.

However, applicant believes that such rechargable battery arrangement cannot possibly work with the electrode configuration proposed in this patent specification. The absence of a self-contained device in the other cases in considered a disadvantage.

It is the object of this invention to provide for the disposal of hypodermic needles and, optionally, syringes associated therewith, which will be a more expeditious and cost-effective disposal of such needles and, where appropriate, syringes.

SUMMARY OF THE INVENTION In accordance with this invention there is provided a hypodermic needle destruction device comprising a housing access aperture through the wall of the housing providing an access path for a hypodermic needle to contact a pair of electrodes within the housing, the electrodes being arranged to operatively contact at spaced positioned along the length thereof a hypodermic needle introduced through said aperture to short-circuit the electrodes and thereby destroy the portion of the needle between the electrodes by electrically generated heat, the device being characterised in that means are provided for allowing the space between the electrodes to diminish when axial pressure is exerted by a part of a syringe or a needle carried thereby on an operative member of the device.

Further features of the invention provide for said operative member of the device to be the electrode nearer the access aperture through the housing therein referred to as the movable electrode in which case the electrode is resiliantly biased towards a terminal position corresponding to maximum spacing between the electrodes and is movable towards the other electrode against said biasing; for means to be provided to limit the spacing between the electrodes to a minimum to avoid short circiuting some together; for the movable electrode to be movable relative to a stud or screw shank extending parallel to the needle axis in which case the biasing of the electrode is conveniently effected by means of a concentric compression spring located between a fairly movable electrode and a head of the stud or screw; and for the aperture to be optionally provided with formations whereby a hypodermic needle base may be disengaged from a hypodermic syringe.

Still further features of the invention provide for the supply circuit of the electrodes to be adapted to supply direct current electrical power to the electrodes from an electrical battery power supply; for the device to be self-contained and to include an electrical battery power supply to be located within the housing; for the batteries to be rechargable in which case the electrical circuit embodies a battery charger circuit adapted for releasable connection to an external supply of electrical energy for charging the batteries; for the battery power supply to be, in the alternative, releasably attached to the device wherein the attachment embodies contacts for connecting the battery to the electrical supply circuit; for the electrical supply circuit to embody a normally open, spring loaded switch connected between the battery power supply and the electrodes; and, for the electrical power supply circuit to embody one or more displays for indicating the state of the battery power supply.

Still further features of this invention provide for the battery power supply to have a capacity of at least 2,2 ampere hours and preferably 2,5 ampere hours at a capacity of 5 hours duration; and for the battery power supply to be nickel cadmium batteries, preferably four of such batteries permanently electrically connected to each other.

Additional features of the invention provide for the housing to have two access apertures, one having means for enabling a friction fit needle to be parted from a syringe, and the other having a convergent zone adapted to grip a needle base and hold it angularly to enable a syringe to be unscrewed therefrom, in which case each access aperture has a pair of electrodes associated therewith.

Alternatively, and as indicated below, it is envisaged that the most preferable arrangement of aperture is a single aperture with no means for assisting in the removal of a needle base but optionally a guide for guiding the axial movement of a hypodermic needle, in use.

In this regard it is to be mentioned that, because the present invention provides a hypodermic needle destruction device which is capable of destroying the entire length of the hypodermic needle down to the base, and also possibly melting the base slightly so that what remains of the needle in the base is sealed off from the atmosphere, it may well be preferable to leave the base on the hypodermic syringe and discard the hypodermic syringe together therewith.

This has the advantage that the base, having become sealed, seals the interior of the hypodermic syringe and, accordingly, any remnants of the contents thereof cannot leak out. This solves the problem of the contents otherwise leaking from the open aperture left if the needle base is removed.

Also, because the needle is destroyed right down to the base, no needle stub remains and, the danger of ruptured waste bin bags or the like is avoided.

This being so, costly rigid bins such as a Sharps bin are rendered unnecessary as the entire syringe and base can now be disposed of in a flexible waste container and can be incinerated therein. The incineration of thick-walled, rigid Sharps bins is thus avoided.

In order that the invention may be fully understood embodiments thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Fig. 1 is an isometric view of one embodiment of the invention; Fig. 2 is an enlarged isometric view of one access aperture, partly broken away; Fig. 3 is a detailed sectional view taken along line III - III in Fig. 1; Fig. 4 is a plan view of the other access aperture to the housing; Fig. 5 is a detailed cross-section through the latter aperture taken along line V - V in Fig.

4; Fig. 6 is a partly schematic plan view showing the interior of the device and the most important components thereof; Fig. 7 is a cross-section taken along line VII - VII in Fig. 6 with the casing complete; Fig. 8 is a block type of circiut diagram of the electrical circuit of the device; Fig. 9a,b & c illustrate, in detail, a pair of electrodes in use in three different degrees of destruction of a hypodermic needle; Fig. 10 illustrates an alternative embodiment to that illustrated in Fig 1; and Fig. 11 is a detailed section taken along line XI to XI in Fig. 10.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS In the embodiment of the invention illustrated in step 1 to 9 of the drawings, the hypodermic needle destruction device comprises a housing, generally indicated by number 1, made of injection moulded plastics material.

The top face 2 of the housing has two elongate access apertures 3 and 4 therethrough each of which provides access to a pair of electrodes 5 attached to the underside of the top 6 (see Fig. 7). In each case the one electrode 5a is inclined away from the top 6 and extends across the axis of the associated aperture at one end thereof. The other electrode 5b is parallel to the top 6 and its end edge 7 terminates midway across the access aperture. Thus, as illustrated in Fig. 7 and 9, when a hypodermic needle (indicated by numeral 8) is passed through the one end of the aperture it will abut the inclined surface of the one electrode Sa and be pushed laterally into contact with the end of the other electrode Sb.

The hypodermic needle will then carry current from one electrode to the other and, with the electrodes suitably energised, the hypodermic needle will become heated to an extremely high temperature between the two positions contacted by the electrodes and will in fact be incinerated. As the hypodermic needle is thrust further against the inclined electrode Sa so the needle will continue to be incinerated until it can no longer be fed towards the electrode.

The above principle is known and, in fact, used in a number of different hypodermic needle incinerators which are currently available.

However, as provided by this invention, the electrodes are not both fixed and there is provided for movement of one electrode towards the other so that the gap between the electrodes can be decreased when certain forces brought to bear on an operating member, which, in this case, is indeed the said other electrode 5b itself. In this particular embodiment of the invention the electrode 5b is held in its horizontal position by means of a compression spring 9 which urges the electrode, which is a flat plate-like member, into engagement with its horizontal mount 10. The compression spring acts between the electrode and a head 11 of a screw 12 on which the spring is mounted and which extends into the mount 10.

With correct selection of the strength of the compression spring 9 the destruction of a needle is now more fully described with particular reference to Figure 9.

Figure 9a illustrates the initial stages of destruction of the hypodermic needle 8 substantially as in prior art similar devices.

Figure 9b illustrates the progress made when the needle is approximately half-way incinerated and illustrates the incineration process taking place in the gap between the electrodes.

When the needle is substantially entirely incinerated the base 13 of the needle which serves to hold the needle in its position and to attach it to a hypodermic syringe 14 (see Fig. 9c) will engage the upper electrode 5b. With somewhat additional force being applied to the needle axially the base 13 engages the electrode 5b and causes it to move towards the lower or inclined electrode 5a thereby decreasing the gap between the electrodes and enabling incineration of the remaining stub of the needle to take place. The incineration process need only cease when the needle is fully incinerated down to the plastic base 13 as shown in figure 9c. In this position, the base will usually have melted to some extent at the point of entry of the needle into same and, in fact, it has been found that the needle has become destroyed for a short distance inside the base.The base then seals off the bore of the part of the needle remaining in the base.

The exact movement of the electorde may take different forms depending on the electrode construction. In Fig 9c the electrode Sb is shown as pivoting about its end opposite the needle engaging end. In the case where two like electrodes are spaced apart, as shown in Fig 6, the whole rigid electrode defining induction (shown as 5c) will be supported at two spaced positions 10a and the movement of either electrode will be roughly straight down.

With a needle incinerated as described above the base can be disposed of in a normal waste disposal system as no sharp stubb remains which can perforate plastic waste bags or the like.

An additional advantage is achieved where the needle is actually left on a disposable hypodermic syringe in consequence of the fact that the bore of the needle, where the same is within the base, becomes sealed due to the molten plastics of the base. In such a case no means, as is or fully described hereinafter, for assisting in the removal of the base from a hypodermic syringe is required and the consequence of this is described more fully below particularly with reference to figures 10 and 11.

Reverting now to the discription of the present embodiment of the invention, and more particularly to the one aperture 3 through the top of the housing, the one end 15 is provided with an inner flange forming a stop 16 for the flange 17 on the base 13 of a hypodermic needle 8 (see Figs 2 and 3) of the friction fit type. In the case of this aperture 3, the flange 17 on the base will engage the stop 16 in the aperture and thereby prevent further feeding of the hypodermic needle towards the electrodes. This stage is chosen such that the entire exposed part of the hypodermic needle will have been incinerated as described above.

Adjacent the end 15 of the aperture 3 are a pair of inwardly directed lips 18, the undersurfaces 19 of which are ramped so that they increase in distance away from the face 2 of the housing with increasing distance from the end 15. Thus, as shown in Fig 3, when a syringe 14 carrying a hypodermic needle base 13 is moved along the slot-like aperture, the ramp surface 19 will engage the flange 17 on the hypodermic needle base to cause it to be moved asially off the spigot 19 carrying the base and to fall down into a receptacle 20 in the form of a drawer. The drawer also receives any remnants of the incinerated needles which fall from the electrodes.

The other aperture 4, on the other hand, and which is. elongate in shape, has two convergent, oppositely directed flanges 21 converging along its length. These flanges 21 are defined by an edge to a metal plate 22 bonded to the upper surface of the housing to provide for wear resistance and long service of the assembly. These flanges 21 are arranged such that, by urging a syringe carrying a screw thread type of hypodermic needle base can be urged between the converging edges to grip the base and thereby enable the syringe to be rotated relative thereto to release the hypodermic needle base and allow it to fall into the receptacle. The converging edges are preferebly serrated to facilitate gripping of the base.

In the above manner the two different methods of attachment of hypodermic needle bases to syringes are catered for in the event that the bases are to be removed from their associated syringes.

However, as indicated above, it may well be desired not to detach the bases of hypodermic needles from their syringes, it being borne in mind that most syringes are also disposable. In this case the housing 22, as shown in Fig. 10, could have a single inlet aperture 23 of substantially circular shape and adapted to accommodate neatly the base to a hypodermic needle. A tubular extension 24 could be provided to the aperture 23 to assist in guiding the hypodermic needle and, more particularly, the base, towards the electrodes 25.

Whatever arrangement is used the electrodes 5 are preferably energised by means of a self-contained battery 26 which, in this case, comprises four 1.2 volt nickel cadmium batteries of a D-size or a 2/3 D-size welded together in series with nickel strips. The capacity of the composite battery is at least 2,5 ampere hours over 5 hours. The batteries are connected to the electrodes by way of a d.c. fuse 27 and a normally open, spring-loaded switch 28 which must be depressed in order to energise the electrodes.

The electrical circuit of the device also embodies three light emitting diodes (LED's) 29, one of which is adapted to become illuminated when the switch 28 is depressed.

The electrical circuit still further includes a battery charger circuit 30 connected by way of fuse 31 to an input plug 32 adapted to releasably receive a power lead. The battery charger circuit is connected to a second of the LED's to indicate when the battery is being c harged and to a third LED to indicate when the charge in the battery is high.

In the manner described above a completely self-contained hypodermic needle destruction device is provided which can simply be charged during periods of non-use. Thereafter it may be transported, for example, on a medical person's trolley, tray or the like, and used to destroy hypodermic needles as patients are administered injections and other medication.

The provision of a destruction device of this nature which is portable and which can be taken to the site at which an injection is actually given, is highly advantageous is that no handling of the hypodermic needles after use is necessary. The only requirement is that they be thrust against the electrodes through one of the apertures with the switch button depressed so that each one becomes incinerated.

The base of the needle can if required then be separated from a syringe by appropriate action in either of the apertures or the entire syringe and needle base discarded as a substantially sealed unit as indicated above.

It will be understood that numberous variations may be made to the embodiments of the invention described above without departing from the scope hereof.

In particular the battery arrangement can be varied widely. The battery may be a separate unit easily associated with the destruction device itself. It may also be a rechargeable battery unit releasably securable to the housing of the destruction device so that a fully charged battery unit can replace a discharged unit as and when required. Also, the recharging arrangement could be varied widely and, in the case of medical personnel who travel in vehicles for an appreciable length of time, the batteries could be charged from a motor vehicle battery through a suitable modifying circuit. An a.c. operated device is also within the scope of this invention.

Claims (18)

1. A hypodermic needle destruction device comprising a housing, and access aperture through the wall of the housing providing an access path for a hypodermic needle to contact a pair of electrodes within the housing, the electrodes being arranged to operatively contact at spaced positions along the length thereof a hypodermic needle introduced through said aperture to short-circuit the electrodes and thereby destroy the portion of the needle between the electrodes by electrically generated heat, the device being characterised in that means are provided for allowing the space between the electrodes to diminish when axial pressure is exerted by a part of a syringe or a needle carried thereby on an operative member of the device.

2. A destruction device as claimed in claim 1 in which means are provided to limit the spacing between the electrodes to a minimum to avoid short circuiting the electrodes together.

3. A destruction device as claimed in either of claims 1 or 2 in which the operative member is the electrode nearer the access aperture (the movable electrode).

4. A destruction device as claimed in claim 3 in which the movable electrode is resiliently biased towards a terminal position corresponding to maximum spacing between the electrodes and is movable towards the other (fixed) electrode against the action of such biasing.

5. A destruction device as claimed in claim 4 in which the movable electrode is movable relative to a stud or screw shank extending parallel to the needle axis and the biasing means is a concentric compression spring acting between a head of the stud or screw and the electrode.

6. A destruction device as claimed in any one of the preceeding claims in which the access aperture is provided with formations whereby a hypodermic needle may be disengaged from a syringe carrying same.

7. A destruction device as claimed in any one of the preceeding claims in which the electrical supply circuit for supplying electrical energy to the electrodes is adapted to supply direct current power to the electrodes in use.

8. A device as claimed in claim 7 in which the device is self-contained and includes an electrical battery power supply.

9. A device as claimed in claim 8 in which the electrical battery power supply is located within the housing.

10. A device as claimed in claim 9 in which the batteries are rechargeable and the electrical circuit embodies a battery charger circuit adapted for releasable connection to an external supply of electrical energy for charging the batteries.

11. A device as claimed in claim 7 in which the electrical battery power supply is releasably attached to the device, the attachment embodying contacts for connecting the battery to the electrical supply circuit.

12. A device as claimed in any one of claims 7 to 11 in which the electrical supply circuit embodies a normally open spring loaded switch connected between the battery power supply and the electrodes.

13. A device as claimed in any one of claims 7 to 12 in which the electrical supply circuit embodies one or more displays for indicating the state of the battery power supply.

14. A device as claimed in any one of the preceeding claims in which the housing has two access apertures, one having means for enabling a friction fit needle base to be parted from a syringe, and the other having a convergent zone adapted to grip a needle base and hold it angularly to enable a syringe to be unscrewed therefrom, each access aperture having a pair of electrodes associated therewith.

15. A device as claimed in claim 9 in which the battery power supply has a capacity of at least 2,2 ampere hours.

16. A device as claimed in any one of claims 8, 9 or 15 in which the battery power supply is a plurality of nickel-cadmium batteries.

17. A device as claimed in claim 16 in which the battery power supply is composed of four nickel-cadmium batteries.

18. A device substantially as herein described and exemplified with reference to the accompanying drawings.